Ultralight particle creation during fresh inflation

TL;DR

This paper investigates the creation of ultralight particles during fresh inflation via Yukawa interactions, suggesting these particles could explain dark energy discrepancies.

Contribution

It introduces a new mechanism for ultralight particle creation during fresh inflation and explores its potential cosmological implications.

Findings

Ultralight particle density increases with faster scale factor growth.

Created ultralight bosons may serve as an alternative to the cosmological constant.

Particle creation is significant during the early nonequilibrium thermal phase.

Abstract

I study ultralight particle creation which becomes from the Yukawa interaction between the inflaton and the thermal bath during fresh inflation. Particle creation is important in the first stages of fresh inflation, when the nonequilibrium thermal effects are important. I find that the number density of the ultralight created particles is more important as the scale factor growth rate is more large (i.e., for $p$ large -- $a \sim t^p$). Ultralight boson fields created during fresh inflation could be an alternative mechanism to cosmological constant to explain the discrepancy between the observed $\Omega_m \simeq 0.2$ and $\Omega_{tot} \simeq 1$, predicted by inflationary models.